Filed: September 24 2025

Court: U.S. Supreme Court

Overview: Amicus brief explaining intellectual disability is a condition that is diagnosed using both quantitative and qualitative data. Standardized IQ tests alone cannot substitute for a complete analysis of intellectual functioning. Under the Supreme Court’s decision in Atkins v. Virginia, executing people with an intellectual disability violates the Eighth Amendment to the U.S. Constitution. When assessing whether a person on death row has an intellectual disability, neither clinicians nor courts should treat the existence of multiple IQ test scores as excuse to avoid the need for a complete quantitative and qualitative analysis.

Excerpt: “Intellectual disability is a condition that is diagnosed using both quantitative and qualitative data, as the diagnosis of the condition is intended to reflect a clinical judgment rather than an actuarial determination. . .As an objective assessment, intelligence quotient (IQ) testing can provide a good estimate of intellectual functioning. However, IQ tests (and the scores obtained from them) have limitations. . .The existence of multiple IQ scores for an individual does not change the requirement for a complete analysis.”

Case Documents:

• Hamm v Smith Amicus Brief

Related Media

• The Arc Press Release